JPH023033B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to rotary fuel injection pumps of the type used to supply metered charges of liquid fuel to compression-ignition internal combustion engines, and more particularly to U.S. Pat. No. 3,883,270. The present invention relates to a new and improved pump plunger displacement control mechanism of the type described in , which is operable to control a metered charge of fuel delivered by a fuel pump.

A principal object of the present invention is to provide a new and improved fuel injection pump in which the metered charge of fuel sequentially supplied to an internal combustion engine is controlled by controlling the displacement of the pump plunger.

Another object of the present invention is to be able to charge fuel more accurately and evenly, and to perform various fuel controls under all operating conditions.
Another object is to incorporate into a fuel injection pump a new and improved pump plunger displacement control mechanism that reduces manufacturing costs.

Other objects of the invention will become apparent from the detailed description of the invention that follows.

The invention will now be described in detail with reference to preferred embodiments thereof, with reference to the accompanying drawings.

In the accompanying figures, an exemplary rotary fuel injection pump 8 of the type used commercially to supply a metered charge of liquid fuel to a compression ignition internal combustion engine is shown as an embodiment of the present invention. It is illustrated in a form that incorporates. The fuel injection pump has a housing 10 which includes a sleeve 14 fitted therein and forming the direct housing for the fuel distributor. Sleeve 14 has a rotor bore 13 in which rotor 12 is rotatably mounted. Sleeve 14 is sealingly mounted within the bore of a hydraulic distributor head 15 mounted within housing 10.

Low pressure pump or transfer pump 1 having an inlet 18 supplied with fuel from a supply tank (not shown)
6 is mounted at one end of the rotor 12 such that it can rotate with the rotor 12. This transfer pump 16
The outlet 20 of is connected via a passage 24 to an annular passage 22 formed in the sleeve 14.

The rotor 12 has a fuel intake port 26 and a fuel discharge port 28. As the rotor 12 rotates, the suction port 26 of the rotor 12 opens into a plurality of inlet passageways 30 evenly spaced around the sleeve 14 in the plane of rotation of the suction port 26.
(of which only two are shown) sequentially communicates with the annular passage 22 and the suction port 26.
The fuel is periodically communicated with the rotor 12 to supply fuel to the rotor 12. Similarly, the discharge port 28 is
The sleeve 14 in the plane of rotation of the discharge port 28
It is adapted to communicate sequentially with a plurality of outlet passageways 32 (only one of which is shown in phantom) spaced evenly around the periphery. As rotor 12 rotates, discharge port 28 sequentially discharges a charge of pressurized fuel from rotor 12 to a plurality of fuel connectors 34, thereby providing a charge of fuel to each cylinder of an associated internal combustion engine (not shown). It has become possible to supply Supply valve 3 located within an internal passage 38 along the axis of rotor 12
6 controls pressurized fuel from flowing back from the discharge port 28.

The rotor 12 is not clearly shown in FIG. 1, but as shown in FIGS. 2 and 3, the rotor 12 is enlarged at the portion where a roller assembly consisting of a roller 56 and a roller shoe 58, which will be described later, is obtained. It has a substantially cylindrical enlarged diameter part 39, and this enlarged diameter part has cutout-like grooves 96 formed at a plurality of spaced apart positions along its periphery to receive the roller shoe 58. Diameter plunger bore 4 at the bottom of the groove
0 is open, and a pair of plungers 42 are installed in each plunger bore, which are arranged diametrically opposite each other so as to be able to reciprocate in the radial direction.
The space between the inner ends of the plunger bore inside the plunger constitutes a high-pressure pump chamber 44 that is communicated with the suction port 26 and the discharge port 28 through the axial passage 38, and is filled with fuel by the rotation of the rotor 12. The system alternates between inhalation and exhalation.

The plungers 42 are surrounded in their plane of reciprocation by a generally circular cam ring 46.
The cam ring 46 is attached to the bore 4 of the pump housing 10 for limited angular movement (rotation).
8, the angular position of which is controlled by a timing piston 50 operatively connected to the cam ring 46 by a connector 52 extending within a radial bore 54 of the cam ring 46. There is.

The cam ring 46 also has an annular cam inner surface 55 having a plurality of inwardly protruding cam lobes (not shown), each of which simultaneously internalizes a pair of diametrically opposed plungers 42. It is arranged so that it is driven in the direction. To this end, a roller assembly including a roller 56 and a roller shoe 58 is disposed between each plunger 42 and cam ring 46 such that it is radially slidably received within a groove 96. Roller 56 functions as a cam follower to convert the cam profile into reciprocating motion of plunger 42.

In operation, as the rotor 12 is driven by the engine via the drive shaft 60, the transfer pump 16
is supplied to the rotor suction port 26 via the inlet passage 30 and further to the high pressure pump chamber 4.
4. In this case, the pair of rollers 56 are positioned at an angle to the cam lobes (not shown) of the cam ring 46, so that the plunger 42 is able to move through the suction port 20 so that fuel can flow into the high pressure pump chamber 44. are adapted to move radially outwardly as they communicate with each inlet passageway 30. As the rotor 12 continues its rotation, the suction port 26 is taken out of communication with the inlet passage 30 and the roller 5 driving the plunger 42
6 rests on a leading surface (not shown) of a cam lobe (not shown) and drives the plunger 42 radially inward to pressurize the charge of fuel in the high pressure pump chamber 44 to a high pressure. At this point, the discharge port 28 rotates into communication with an outlet passage 32 connected to one of each cylinder of the engine to inject a charge of fuel under pressure into that cylinder.

As the rotor 12 continues to rotate, the process of sequentially supplying a charge of fuel to each cylinder of the internal combustion engine is repeated in relation to the rotation.

During the pump suction time, there is almost no restriction on the flow of fuel from the transfer pump 16 to the high-pressure pump chamber 44, so that the high-pressure pump chamber 44 is charged with fuel under positive pressure. Fuel evaporation problems that would occur if the pump chamber 44 were filled under negative pressure are eliminated.

According to the invention, pump plunger stroke control means are provided for controlling the amount of fuel injected during each pump stroke without reducing the pressure of the pressurized fuel in the high pressure pump chamber 44. The control means is a new and improved mechanical control mechanism that controls the displacement of plunger 42 and thereby the amount of fuel injected during each pump stroke.

As shown in FIGS. 1, 4, and 5,
A control ring 68 is rotatably mounted around the sleeve 14 between the enlarged diameter portion 39 of the rotor 12 and the axially opposed end faces of the hydraulic distributor head 15. In the end face of the distributor head 15 facing the control ring 68, three recesses 72 having surfaces 74 inclined with respect to the end face are cut at equiangular intervals along the end face. There is. Only one of them is shown in FIG. 1, and the cutting state of the recess 72 is shown in cross section in FIG. Each of the inclined surfaces 74 of these three recesses 72 is engaged with a follower button 76 which is also attached to the control ring 68 and spaced equiangularly apart in the circumferential direction.

The follower button 76 is connected to the inclined surface 74 of the recess 72.
When pushed downwardly as seen in FIG.
Thus, when rotation of control ring 68 causes recess 72 to move from side to side relative to follower button 76 as seen in FIG. It is designed to be displaced in the direction.

The angular position of control ring 68 is adapted to be controlled via a connector 82 received within a cutout 84 thereof. The connector 82 is adapted to be driven by a plunger 86 mounted within a transverse bore 88. The angular position of plunger 86 within bore 88 may be controlled by one or more control mechanisms (not shown) that control operation of the fuel injection pump. As will become apparent, plunger 86 controls pump plunger 42 by controlling the angular position of control ring 68.
, and thus the charge of fuel delivered by the fuel pump during the pump stroke.

In FIGS. 2 to 4, each roller shoe 58
is a sliding engagement between a fixed guide portion 90 on one side of the roller shoe 58 and an adjustable stop member 92 (also functioning as a guide) on the opposite side of the roller shoe. It is equipped to obtain. Another fixed guide member 94 is provided to support and guide the stopper member 92. These two fixed guide members 90 and 94 provided opposite each other are installed in grooves 96 of the rotor enlarged diameter portion 39, and the rotor enlarged diameter portion is installed in order to clearly position the fixed guide members 90 and 94. It has an integral stub shaft 99 received within a transverse bore 100 aligned and drilled in the opposed side walls of section 39 . The fixed guide member 90 facing the stopper member 92 has a flange portion 102 projecting in the circumferential direction at one end in the axial direction.
6 to prevent them from being displaced beyond a predetermined position axially towards the control ring 68. Also, all roller shoes 58 and rollers 56 are attached to a retaining ring 104 (FIGS. 1 and 4).
(See Figures) to prevent axial displacement beyond a predetermined position in opposite directions, thereby maintaining roller shoe 58 and roller 56 in proper alignment with pump plunger 42.

The stop member 92 and the adjacent fixed guide member 94 have sliding engagement portions to allow the stop member 92 to be adjusted axially and radially relative to the adjacent roller shoe 58. In the illustrated embodiment, this sliding engagement portion is connected to the fixed guide member 9.
4 and an elongated lip 108 on stopper member 92 received therein.
The lip portion 108 is inclined at an angle of, for example, 26 degrees with respect to the axis of the rotor 12, so that by adjusting it axially, the stop member 92 can be adjusted radially. ing. Stop member 92 has a circumferentially projecting and axially extending elongate abutment lip 112 which faces and engages a corresponding chamfered axial edge 116 of roller shoe 58. Slanted inner edge 1 that can be combined
14 (see Figure 3). Thus, at each axial position of stop member 92, its abutment lip 112 abuts roller shoe 58 and thereby controls the radially outward displacement of roller shoe 58 and corresponding pump plunger 42. It's summery. Alternatively, as an alternative to the illustrated embodiment, the stop member 92 is mounted for reciprocating motion parallel to the axis of the rotor 12 and is inclined relative to the axis of the rotor 12 so that the stop member 92
8 has an elongated abutment lip 112 engageable by a corresponding angled abutment edge 116 to adjust the axial position of the stop member 92 radially outwardly of the corresponding pump plunger 42. You may begin to adjust the limits of your exercise.

In Figures 3 and 4, tension coil spring 1
20 is attached below the inner edge of the stopper member 92, and this tension coil spring 120
is adapted to maintain stopper member 92 in engagement with control ring 68 with the aid of centrifugal force acting on stopper member 92 . Further, in order to place the tension coil spring 120 in a tensioned state, the rotor enlarged diameter portion 39 and the stopper member 9
2 and have ends 122, 123 which are received within corresponding holes formed in 2. The tension coil spring 120 has a stopper member 92 that is connected to the sliding engagement portion 108,
110 so that the stop member 92 is freely axially adjustable by the control ring 68. ing. Thus, the control ring 68 is adjusted angularly,
Engagement of the follower button 76 with the sloped surface 74 of the recess 72 causes a corresponding axial movement of the control ring 68 and a corresponding movement of the stop member 92.
By adjusting the plunger 4 in the axial direction,
The outward stroke of 2 is regulated to control the charge of fuel delivered with each pump stroke.

Stopper member 9 for all plungers 42
2 are regulated simultaneously by the control ring 68 such that, depending on any angular setting of the control ring 68, the pairs of opposed plungers 42 cause an equal charge of fuel to each cylinder of the associated internal combustion engine. Jet-fed.

The radially outward movement of the roller shoes 58 is stopped by the roller shoes 58 engaging the stopper members 92, and the impact force exerted by each roller shoe 58 on the corresponding stopper member 92 is directed radially outwardly. is proportional to the square of the speed of movement of the roller shoes 58, thereby reducing the speed of radially outward movement of the roller shoes 58 caused by the high velocity impact force applied by each roller shoe 58 to its corresponding stop member 92. The slope of the cam lobe is preferably gentle, as shown in the aforementioned US Pat. No. 3,883,270, so that stresses are minimized.

From the foregoing, it can be seen that in accordance with the present invention, the metered charge of fuel delivered with each pump stroke can be accurately calculated without resorting to low pressure delivery or pumping of a portion of the pressurized fuel by the fuel pump. Moreover, it can be reliably controlled mechanically. Furthermore, according to the present invention, by controlling the axial position of one control ring 68 by rotating it, a variety of controls can be performed very simply and efficiently.

Although the present invention has been described in detail with respect to specific embodiments thereof, the present invention is not limited to such embodiments, and various modifications and omissions can be made within the scope of the present invention. This will be clear to those skilled in the art.

[Brief explanation of drawings]

FIG. 1 is an illustrative front view, partially cut away, showing an embodiment of a rotary fuel injection pump according to the present invention. 2 is an illustrative enlarged exploded perspective view showing a part of the rotor of the fuel injection pump shown in FIG. 1. FIG. FIG. 3 is an illustrative longitudinal sectional view showing an enlarged part of the rotor. FIG. 4 is an illustrative enlarged partial longitudinal cross-sectional view taken along line 4--4 of FIG. FIG. 5 is an illustrative enlarged partial longitudinal sectional view showing a cam and follower adjustment device of a rotary fuel injection pump according to the present invention. 8~Rotary fuel injection pump, 10~Pump housing, 12~Rotor, 13~Rotor bore, 1
4~Sleeve (housing), 15~Hydraulic distributor head, 16~Transfer pump, 18~
Inlet, 20 - outlet, 22 - annular passage, 24 - passage, 26 - suction port, 28 - discharge port, 30
- inlet passage, 32 - outlet passage, 34 - fuel connector, 36 - supply valve, 38 - axial passage, 39 -
Rotor enlarged diameter section, 40 - plunger bore, 42 - plunger, 44 - high pressure pump chamber, 46 - cam ring, 48 - bore, 50 - timing piston, 5
2 - Connector, 54 - Radial bore, 55 - Cam inner surface, 56 - Roller, 58 - Roller shoe, 60
~ Drive shaft, 68 ~ Control ring, 72 ~ Recess, 7
4 - Inclined surface, 76 - Follower button, 80 - Interval, 82 - Connector, 84 - Notch, 86 - Plunger, 88 - Lateral bore, 90 - Fixed guide member, 92 - Stopper member, 94 - Fixed guide member , 99~stub axis, 100~lateral bore, 10
2 - lip part, 104 - retaining ring, 108 - lip part, 110 - slot, 112 - contact lip part, 114 - inner edge, 116 - axial edge, 120 - tension coil spring, 122, 12
3 ~ End.

Claims (1)

[Claims] 1 A rotary fuel injection pump for an internal combustion engine, comprising a housing 14 having a cylindrical rotor bore 13, an inlet passage 30 and an outlet passage 32 opening into the bore, and rotatable about a central axis within the rotor bore of the housing. a plurality of angularly spaced, radially extending plunger bores 40 supported by the plunger bores 40 and an internal passageway that connects to the inner end of the plunger bores at one end and terminates in the suction port 26 and the discharge port 28 at the other end. 38, and the suction port and the discharge port alternately communicate with the inlet passage 30 and the outlet passage 32 as the rotor rotates within the rotor bore. , further including a plurality of pump plungers 42 reciprocatably mounted within and along the plunger bores, and within a groove 96 formed in a portion of the rotor adjacent a radially outer end of the plunger bores. a plurality of mounted roller 56 and roller show 58 assemblies and an inwardly facing cam contour surface surrounding the rotor and driving the pump plunger radially inwardly through the roller and roller show assemblies; a cam ring 46 having a cam ring 46; and pump plunger stroke control means for adjustably limiting the radially outward stroke of the pump plunger to control the amount of fuel delivered, the pump plunger stroke control means having a cam ring 46 with a slope sliding relative to the rotor. a stop member 92 supported so as to be movable radially and axially relative to the rotor by engagement and correspondingly moved radially relative to the rotor by being moved axially relative to the rotor; the stop member is engageable with the roller shoe 58 to limit its radially outward stroke and means 68 for adjustably displacing the stop member axially relative to the rotor;
A rotary fuel injection pump comprising: 74, 76.